Using an inbred strain of pigmented rabbits, a model of massive periretinal proliferation (MPP) will be developed; the model is based on previous successes with freshly harvested or cell cultured retinal pigment epithelium (RPE) cells autotransplanted into the vitreous cavity of an outbred strain. Intravitreous strands, retinal puckers and preretinal membranes, as well as retinal traction detachments all form, thus resembling human MPP, a common complication of retinal surgery. RPE cells will be cultured and injected in equal numbers into the vitreous cavity of inbred rabbits. To determine the rate of growth of the transplant nuclei, of cells recovered from the vitreous cavity will be isolated and counted. 3H-thymidine and 14C-uridine autoradiography of isolated nuclei will be used to gauge cell viability and the corrected labelling index throughout a three week peroid of MPP. The effect of the ocular inflammation on the course of MPP will be investigated in the presence of vitreous humor derived from rabbits with scleral inflammation. Chemotherapy, based on (1) interruption of specific progression points in the RPE cell cycle, (2) inhibition of matrix synthesis and (3) interfering with contractile elements will be tested. For those agents deemed to be most effective in disrupting the MPP syndrome, histological and electron microscopic examination of ocular tissues will be undertaken to identify any attendant drug-related ocular toxocities. The goal is to find means of preventing the full-blown consequences of MPP in patients identified as likely candidates.